Continuous furnace



July 23, 1935. M. FoURMl-:N'r 2,008,695

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Patented July 23, 1935 UNITED STATES PATENT OFFICE CONTINUOUS FURNACE Marcel Fourment, `Paris, France Application July 7, 1933, Serial No. 679,439 lin France March 10, 1933 e claims. I(c1. 19e-219) heated again with the articles that it carries.

when it enters the furnace; the calories taken `l up by the hearth during its passage in the furnace are then dissipated in pure waste.

Moreover, in certain cases', the cold hearth must enter the hottest part of the furnace andv its temperature can equal that of the furnace only after a certain working time, and this is clearly disadvantageous as regards the utility of the furnace.

There have been invented also furnaces called beam furnaces in which the advance of the articles is obtained by what may be called longitudinal beams or girders which rise and fall periodically in channels provided in the hearth or sole of the furnace; this remedies the disadvantages mentioned above, but this method, in the different modes of carrying it into effect hitherto known, renders possible the transportation only of articles of fairly large dimensions; when small articles are to be reheated, it is necessary to place them on trays and the disadvantages mentioned above (dead weight to be heated) are again met with aggravated by complication in management and in maintenance.`

In the method of conveyance of articles for continuous furnaces forming the subject matter of the present invention, which remedies these disadvantages, there is used a double group of bars or cables for the purpose of producing by elementary advances the progress of articles, even of small dimensions, through the furnace. These bars or cables are placed parallelly to one another so that there is only a very small space between each of them in order that articles of small dimension may be supported without there 50 being danger of their passing through the hearth thus constituted.

In the accompanying drawings, which represent by way of example a form of construction of a conveyor applied to a continuous furnace:-

Fig. 1 is a longitudinal section of the furnace,

Fig. 2 is a plan View partly in section,

Fig. 3 is a partial sectional view of the hot end of the furnace,

Fig. 4 is a transverse section of the furnace,

Figs. 5, 6 and 7 show the different groups of eccentric pulleys supportingthe bars or cables, and

Fig. 8 shows the system of gearing of the shafts carrying the eccentric pulleys,

Fig. 9 is a diagrammatic general vertical sec- 5 tion of a modification,

Fig. 10 is a section corresponding to II-II of Fig. 9.

Fig. 11 is a modification of Fig. 10 showing another controlling arrangement. 10

According to the invention, the furnace i of the type called a continuous furnace-i. e., of the type in which the articles to-be heated or reheated are given a continuous progressive movement from one end of the furnace to the other l5 comprises secondary transverse shafts 2, which are of any suitable number and are mounted in any Asuitable manner by means of bearings. Each of these shafts has fixed to it eccentric pulleys 3, t, which are mounted eccentrically on it, have all the same eccentricity, but are displaced in `relation to each other by 180 as is shown in Fig. 6, so that for a given position of the shaft 2, the pulleys 3 for example the even-number pulleys on the shaft are in a high position and the odd-number pulleys i are in a low position.

Each shaft 2 carries also at its free end, which is outside the furnace, a chain wheel 5 that serves for its operation. These pulleys 3 and have their peripheries suitably formed so as to present a channel in which a bar or a metallic cable 6 or 'l can rest, the Whole of the bars or cables being thus divided into two groups of which one group, that composed of the bars 6 for example, bears on the eccentrics that are in a high position at a given moment, and the other group, that composed of the bars on the eccentrics then in a low position.

At the cold end of the furnace there is arvranged transversely a shaft 8 carrying likewise eccentrics of a number equal to that of the pulleys 3, of each shaft 2 and having for example the same eccentricity. These eccentrics are keyed on the shaft 8 and are likewise displaced in relation to one another by 180 so that in a manner analogous to that of the pulleys of the shafts 2, at a given moment the even-number eccentrics may be for example4 in a high position and the odd-number eccentrics in a low position.

On these eccentrics there are mounted straps 9 to which are fixed the bars 6 and 'l whose other ends are connected by means of springs i6 to an angle-iron Il rigidly attached to the frame of the furnace. .These springs (for example helical springs) should have suitable characteristics so as to maintain the bars or cables suiiciently stretched notwithstanding their Weight and that of the articles carried, and to be capable of sus- 00 e all the shafts 2 firmly up with the shaft 8. i

'I'he endless chain I2 may have any suitable tension device such as wheels I5 (Fig. 8) 'which are mounted on brackets I6, and the position as to height of which is capable of regulation so as to'secure the proper coming into engagement of the chain with the motor wheels 5.

As all the shafts 2 and 8 are keyed in the same angular position in relation to one another so that all the even-number eccentrics and pulleys of each of the shafts are at the same time in a high position for example whilst all the odd-number eccentrics or pulleys are in a low position, or vice-versa, the bars resting on these pulleys form two platforms or hearths of which one is in a high position while the other is in a low position and each of which can be given a movement of translation under the action of the shaft 8.

'Ihe trajectory described by a point on a bar or on a cable is a circle the diameter of which is equal to that of the eccentricity (sic) of the pulleys; but if it were considered necessary the mechanism could be modified so that this trajectory would be an ellipse, a rectangle, or any other figure.

The furnace may comprise any suitable heating arrangement. In the example shown, burners such as I1 are arranged at one of the ends of the furnace and at thevupper part, the hot gases circulating about the articles to be treated through, conduits I8 (Fig. 4) to pass under the sole I9 of the furnace and afterwards to be delivered to the flue 20.

The operation is as follows:-

When the motor operates the shaft 8, and, by means of the chain I 2 and the wheels 5, the shafts 2, all these shafts have the same movement in space and in time. Each of the groups of evennumber or odd-number bars or cables forming the two platforms or hearths then has a rotational movement in a vertical plane, these two rotational movements being displaced in relation to each other by It will thus be seen that an article placed on the conveyor thus constituted is raised by the group of even-number bars, for example, which communicates to it a slight forward progression. When this group of bars descends again, the other group of bars rises, picks the article up again, and causes it to execute a fresh forward progression, after which the rst group of bars cornes into action again. For one revolution of the motor shaft 8, each article thus progresses by an amount equal to double the diameter of the circle of eccentricity of the eccentrics mounted on the shaft 8.

The respective diameters of the eccentrics carried by the shafts 2 and by the motor shaft 8 determine the form of the movement of the platforms or hearths, this movement being circular in the case in which all the eccentrics have the same diameter and elliptical in the case in which the diameter of the eccentrics 8 differs from the diameter of the eccentrics 2, so that vthe form of the movement can be varied according to requirement to obtain a progression with a more or less pronounced movement of ascent and descent of the articles to be conveyed.

Moreover, in order to obtain a more continuous movement of the articles .to be conveyed, there might be employed more than two groups of cables or bands, the conveyance then taking place more regularly.

The system for transmitting movement to the shafts 2 might be different from that described; the system comprising a worm and motor shaft might be used and would not present the inconvenience of having to take upplay.

This conveying arrangement avoids the loses of heat due to the successive reheating and recooling of the conveying hearth that are inevitable when the conveyor is constituted by an endless hearth, entering and issuing from the furnace continually. Moreover the bars or cables and also the eccentric pulleys may be given thicknesses as small as possible. Grating may be constituted of bars sufficiently close together capable of supporting articles of any'desired dimensions so that it is not necessary to convey the articles to be heated in cases which must also be heated and thus involve loss of heat.

Finally, furnaces of any desired length may be made by arranging as many secondary shafts 2 as may be necessary for supporting the cables.

There may be used any system of heating, whether employing solid, liquid or gaseous fuel, or employing electric resistances.

The invention is applicable for the conveyance of articles in furnaces and for all other applications.

In the form of carrying out the invention shown in Figs. 9 to 11, the surface of the wires or bars supporting the objects to be moved and constituting -a platform is divided into two sections 2| and 22 which engage motive elements such as drums or other motive elements 23 and 24 mounted on diierent shafts 25 and 26 and controlled either by a common motive element or by different motive elements enabling rotational movements of any desired sense to be impressed on the shafts 25 and 26.

The shafts 25 and 26 being put into rotation in the same sense, the apparatus works as in the case of Figs. 1 to 8-i. e., the articles'arranged at the entry end 21 of the furnace will be carried in the interior of the furnace from right to left and will arrive at the opposite end of the furnace I.

If, on the contrary, the shaft'26 is caused to rotate in a sense different from that of the shaft 25, there will be produced, by the section 22 of the platform, a direction of circulation different from that of the section 2I.

In the particular form of construction indicated in Fig. 10, an article placed on the platform section 2| at the left-hand end of the furnace, will proceed to the right-hand end of this furnace, whilst an article placed on the platform section 22 at the right-hand end will proceed to the left-hand end of the furnace.

Such an arrangement is particularly useful for producing the progressive heating of certain articles up to a predetermined temperature and for submitting these articles afterwards to a progressive cooling.

In order to produce a treatmentof this nature with the constructional form of the arrangement according to Figs. 9 to 1l, the articles are placed at the right-hand end of the furnace on the section 22 of the platform, the said articles being subjected to a progressive heating as far as the left-hand end of the furnace, where a mechanical L about an excellent thermic cycle, for the articles,

' its own controlling shaft.

which are cooled during their carriage by thek 1. Progressively heating articles `from the ordinary temperature to a predetermined temperature a't which they are removed from the furlnace. This is the case for example of the problem of the tempering, the annealing, the hardening, etc. of metallic parts. L

2. Annealing articles or parts which are placed not into the furnace and which should be cooled progressively according to a predetermined law; this is the case for example of the annealing of glass articlesthat have just been made.

3. Heating articles progressively from the ordinary temperature to a predetermined temperature and bringing them back afterwards progressively to the ordinary temperature. This is the case for example of decoration on glass or of the thermic treatment of metals and alloys.

The platform of the furnace might be divided 'into any desired number of sections each having There might for example, as indicated in Fig.

. 11, be provided a central section 28, with its shaft 29 and lateral sections 30, 3l which are of a.

width equal to or different from that of the central section 28 and are adapted to be controlled either by a common shaft 32 or by different shafts provided with operating arrangements enabling them to be operated in the same sense as the central shaft 29 or in a sense different from that of the rotation of this shaft and at an equal or different speed.

What I claim is:-

1. In a device for conveying articles to be treated in continuous furnaces, a number of groups of bars forming platforms, external drive means for causing said groups of bars to receive each v,in turn a longitudinal horizontal advance movement in at least one direction, internal means independent of said first mentioned means for causing said bars to receive a vertical movement, while being horizontally moved, and means for maintaining the bars under tension and tending to move them in a direction opposite to that im-` parted by the drive means, while permitting said bars' at all times to elongate under the influence of the driving mechanism.

2. In a device for conveying articles to be treated in continuous furnaces, a number of groups of bars forming platforms, a controlling shaft located at one end of the furnace and external to said furnace, cams keyed on said shaft, straps connected with said cams, bars secured to said straps, internal means independent of said first mentioned means for causing said bars to receive a vertical movement, while being horizontally moved in at least one direction, and means for maintaining the bars under tension and tending to move them in a direction opposite ,to that imparted by said controlling shaft, while permitting said bars at all times to elongate under the influence of the drive from said control shaft.

3. In a device for conveying articles to be treated in continuous furnaces, a number of groups vof bars forming platforms, a controlling shaft located at one end of the furnace and external to said furnace for positively movi g the bars in at least one direction, cams keye on ,saidV shaft, straps connected with said cams, bars secured to said straps, a number of transverse shafts located in the furnace, groups of cams keyed on said transverse shafts and synchronized with said external shaft, and means for maintaining the bars under tension and tending to move them in a direction opposite to that imparted by the controlling shaft, while permitting said bars at all times to elongate under the influence of the driving mechanism actuated by said controlling shaft.

4, In a device for conveying articles to be treated in continuous furnaces, a number of groups of bars forming platforms, a controllingshaft located at one end of,l the furnace and external to said furnace for positivelymoving the bars in at least one direction, cams keyed on said shaft, straps connected with said cams, bars secured to said straps, a number of transverse shafts loe cated in the furnace, groups of cams keyed on said shafts and synchronized with said external shaft, springs located at a point remote from the controlling shaft, for maintaining the bars under tension and tending to move them in the direction opposite to that imparted by the drive means actuated by the control shaft, while permitting said bars at all times'v to elongate under the influence of the driving mechanism.

5. In a device for conveying articles to be treated in continuous furnaces, two groups of thin bars placed sidewise adjacent with each other without undue clearance, external means for causing said groups of bars to receive each in turn a longitudinal horizontal advance movement in at least one direction, internal means independent of said rst mentioned means for causing said bars to receive a vertical movement, 'while being horizontally moved, and means for maintaining the bars under tension and tending to move them in a direction opposite to that imparted by the drive means, while permitting said bars at all times to elongate under -the influence of the driving mechanism.

6.v In a device for conveying articles to be treated in continuous furnaces, two groups of thin bars placed sidewise adjacent with each other without undue clearance, external means for causing said groups of bars to receive each in turn va longitudinal horizontal advance movement in at least one direction, internal means independent of said first mentioned means for causing said4 bars to receive a vertical movement, shafts located outside said furnace, cams mounted on said shafts, straps surrounding said cams, and con- .stituting separate groups of-control for the corfluence of the driving mechanism. MARCEL FOURMENT. 

